SMART International Symposium for Next Generation Infrastructure: Spatial Network Modelling for...
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Monday, 30 th September 2013: Business & policy Dialogue Tuesday 1 October to Thursday, 3 rd October: Academic and Policy Dialogue www.isngi.org ENDORSING PARTNERS The following are confirmed contributors to the business and policy dialogue in Sydney: Rick Sawers (National Australia Bank) Nick Greiner (Chairman (Infrastructure NSW) www.isngi.org Spatial Network Modelling for Sanitation Planning in Informal Settlements Presented by: Dr Tomas Holderness SMART Infrastructure Facility, University of Wollongong
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A presentation conducted by Dr Tomas Holderness SMART Infrastructure Facility, University of Wollongong. Presented on Thursday the 3rd of October 2013 Limited water and sanitation infrastructure in rapidly urbanising informal settlements can present significant health and environmental risks to populations in developing nations. Where formal pipe networks are not available,road-based sewage treatment-transportation options have been cited as a viable alternative. However, little research has been undertaken to evaluate the long term operational costs of such systems. In this paper we present an evaluation of network modelling, as a novel method to evaluate the costs of road-based sewage treatment transport options. Such analysis is made possible using crowdsourced, open geospatial data which allow us to examine costs based on different spatio-topological network configurations. It is envisaged that such a tool could be used by engineers as part of the sanitation planning process, to evaluate sanitation network implementation options. The paper includes a case-study based on the Kibera settlement in Kenya
Transcript of SMART International Symposium for Next Generation Infrastructure: Spatial Network Modelling for...
Monday, 30th September 2013: Business & policy Dialogue
Tuesday 1 October to Thursday, 3rd October: Academic and PolicyDialogue
www.isngi.org
ENDORSING PARTNERS
The following are confirmed contributors to the business and policy dialogue in Sydney:
Rick Sawers (National Australia Bank)
Nick Greiner (Chairman (Infrastructure NSW)
www.isngi.org
Spatial Network Modelling for Sanitation Planning in
Informal Settlements
Presented by: Dr Tomas Holderness SMART Infrastructure Facility, University of Wollongong
KSpatial Network Modelling for Sanitation Planning in
Informal Settlements
Tomas Holderness1, Ruth Kennedy-Walker2, David Alderson2 & Barbara Evans3
1 University of Wollongong, 2 Newcastle University (UK), 3 University of Leeds (UK)
The Sanitation Infrastructure Crisis• Rapid city densification
• Peri-urbanisation growth
• Informal infrastructure
Image credits: [1] Nils Gilman/io9.com; [2] PIUS UTOMI EKPEI/AFP/Getty Images
The Sanitation Crisis
Image credits: [1] WHO/UNICEF
Critical Infrastructure?
Image credits: [1] Florian Erzinger
A “frogman” manually emptying a pit latrine in Dar es Salaam
The Solution?
Vacutug:• Vacuum pump truck• 0.5m3 capacity• 5 Km/h speed
Image credits: [1] Rémi Kaup; [2] Sustainable Sanitation Alliance
Transfer stations
Image credits: [1] Authors; [2] Tilley et al. 2008
• Reduce Vacutug travel time
• Situated at the edge of informal settlement
• Serviced by large collection tanker
• Location is key to reduce time and costs
A new approach
Image credits: [1] Map Kibera
• Crowd-sourced mapping for spatio-toplogical network modelling• Land cover, road/path network, amenity location
• Optimise location of transfer stations to minimise transport time• Iterative, weighted Dijkstra’s algorithm
• Open-source tool to support Engineers in the sanitation planning process
Methodology
Data preprocessing & spatial database
construction
MCE site analysis
Create network
Network Analysis
Data preprocessing
Image credits: [1] Google, Digital Globe
Data preprocessing
Data downloaded from Open Street Map and Map Kibera:
• Total area ~ 3000 Km2 (inc. Kibera)• 6,557 points of interest• 9,222 linear features (roads, waterways, railways etc.)• 7,800 polygon features• 582 water and sanitation features in Kibera:
• 158 public toilets• 8 bio-centres
• Data loading into PostGIS using Python (GDAL/OGR, Fiona, GeoAlchemy2)
Multi-criteria evaluation of transfer station locations
• MCE analysis implemented using PostGIS
• Transfer station location parameters:• Area ≥ 64m2
• Kibera boundary ≤ 50m• Nearest road ≤ 5m
Image credits: [1] Map Kibera
Network Creation
• Spatio-topological model created using PostGISschema and NetworkX interface
• 19,558 edges (Nairobi and Kibera)• 4,686,483 Km of road and footpath• 16,347 nodes (junctions, toilets, transfer stations,
treatment plant)
Network Analysis
Total time for shortest network path:• Each toilet to transfer station (158 trips)• Accumulated waste, transfer station to treatment (7.9 trips)
• Vacutug capacity: 500 liters• Large tanker capacity: 10,000 liters
Results
Image credits: [1] Map Kibera
Results
Image credits: [1] Google, Digital Globe
Conclusions
• Crowd-sourced map data enabling network analysis
• Spatio-topological network modelling within GIS framework useful for sanitation planning
• Limited by data quality and availability
• Next steps,• Attributing cost to networks
• Business case• Tie to sanitation value chain
• Compare against pipe sewerage network• Apply to other networks (solid waste etc.)
